Good point. —Dan Veit Elser <ve10@cornell.edu> wrote: -----

On Jul 27, 2016, at 6:35 PM, Bill Gosper <billgosper@gmail.com> wrote:

is an odd function of t? —rwg

The right question to ask, when it’s multivalued and analytic, is whether the Riemann surface has “odd symmetry”: (z1,z2) \in C^2 is on the surface iff (-z1,-z2) is on the surface. When this is true in an open neighborhood of the origin — as this case which has a regular Taylor series with only odd powers — then it holds for the entire Riemann surface by analytic continuation. -----